From b271a6e25144be8cf872d028bb82336b5da2074c Mon Sep 17 00:00:00 2001
From: rsgowman <rgowman@google.com>
Date: Thu, 21 Jun 2018 13:59:56 -0400
Subject: Initial creation of the local serializer. (#1415)

Added a single, basic test as a motivator.
---
 .../firebase/firestore/local/local_serializer.h    | 109 +++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 Firestore/core/src/firebase/firestore/local/local_serializer.h

(limited to 'Firestore/core/src/firebase/firestore/local/local_serializer.h')

diff --git a/Firestore/core/src/firebase/firestore/local/local_serializer.h b/Firestore/core/src/firebase/firestore/local/local_serializer.h
new file mode 100644
index 0000000..c1b4761
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/local/local_serializer.h
@@ -0,0 +1,109 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_LOCAL_LOCAL_SERIALIZER_H_
+#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_LOCAL_LOCAL_SERIALIZER_H_
+
+#include <memory>
+#include <vector>
+
+#include "Firestore/core/src/firebase/firestore/model/maybe_document.h"
+#include "Firestore/core/src/firebase/firestore/nanopb/reader.h"
+#include "Firestore/core/src/firebase/firestore/nanopb/writer.h"
+#include "Firestore/core/src/firebase/firestore/remote/serializer.h"
+#include "Firestore/core/src/firebase/firestore/util/status.h"
+
+namespace firebase {
+namespace firestore {
+namespace local {
+
+/**
+ * @brief Serializer for values stored in the LocalStore.
+ *
+ * Note that local::LocalSerializer currently delegates to the
+ * remote::Serializer (for the Firestore v1beta1 RPC protocol) to save
+ * implementation time and code duplication. We'll need to revisit this when the
+ * RPC protocol we use diverges from local storage.
+ */
+class LocalSerializer {
+ public:
+  explicit LocalSerializer(const remote::Serializer& rpc_serializer)
+      : rpc_serializer_(rpc_serializer) {
+  }
+
+  /**
+   * @brief Encodes a MaybeDocument model to the equivalent bytes for local
+   * storage.
+   *
+   * @param document the model to convert.
+   * @param[out] out_bytes A buffer to place the output. The bytes will be
+   * appended to this vector.
+   * @return A Status, which if not ok(), indicates what went wrong. Note that
+   * errors during encoding generally indicate a serious/fatal error.
+   */
+  // TODO(rsgowman): If we never support any output except to a vector, it may
+  // make sense to have LocalSerializer own the vector and provide an accessor
+  // rather than asking the user to create it first.
+  util::Status EncodeMaybeDocument(const model::MaybeDocument& maybe_doc,
+                                   std::vector<uint8_t>* out_bytes) const;
+
+  /**
+   * @brief Decodes bytes representing a MaybeDocument proto to the equivalent
+   * model.
+   *
+   * @param bytes The bytes to convert. It's assumed that exactly all of the
+   * bytes will be used by this conversion.
+   * @return The model equivalent of the bytes or a Status indicating what went
+   * wrong.
+   */
+  util::StatusOr<std::unique_ptr<model::MaybeDocument>> DecodeMaybeDocument(
+      const uint8_t* bytes, size_t length) const;
+
+  /**
+   * @brief Decodes bytes representing a MaybeDocument proto to the equivalent
+   * model.
+   *
+   * @param bytes The bytes to convert. It's assumed that exactly all of the
+   * bytes will be used by this conversion.
+   * @return The model equivalent of the bytes or a Status indicating what went
+   * wrong.
+   */
+  util::StatusOr<std::unique_ptr<model::MaybeDocument>> DecodeMaybeDocument(
+      const std::vector<uint8_t>& bytes) const {
+    return DecodeMaybeDocument(bytes.data(), bytes.size());
+  }
+
+ private:
+  void EncodeMaybeDocument(nanopb::Writer* writer,
+                           const model::MaybeDocument& maybe_doc) const;
+  std::unique_ptr<model::MaybeDocument> DecodeMaybeDocument(
+      nanopb::Reader* reader) const;
+
+  /**
+   * Encodes a Document for local storage. This differs from the v1beta1 RPC
+   * serializer for Documents in that it preserves the updateTime, which is
+   * considered an output only value by the server.
+   */
+  void EncodeDocument(nanopb::Writer* writer, const model::Document& doc) const;
+
+  const remote::Serializer& rpc_serializer_;
+};
+
+}  // namespace local
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_LOCAL_LOCAL_SERIALIZER_H_
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